Ciena returns to S&P 500 after getting booted 17 years ago

Ciena, a prominent player in networking hardware, is set to rejoin the S&P 500 index, marking its return after being removed 17 years ago. Following the announcement, the company's stock experienced a surge during after-hours trading. The change comes as Ciena takes the place of Dayforce, a human resources software company recently acquired by private equity firm Thoma Bravo for a staggering $12.3 billion. Ciena specializes in high-speed fiber optical networks and has reported significant revenue contributions from major clients, including an unnamed cloud provider accounting for nearly 18% of its revenue in the 2025 fiscal year, and AT&T contributing around 11%. In the past year, Ciena's market capitalization has nearly tripled. Historically, stocks added to the S&P 500 tend to see price increases as fund managers acquire shares in anticipation of the index change. Other technology firms such as AppLovin, Datadog, DoorDash, and Robinhood made their S&P 500 debut in 2025. This return to the index is significant for Ciena, which first joined in 2001 during the dot-com and telecom boom, only to be removed in 2009 when Visa took its spot. The current surge in demand for data center infrastructure, driven by the rise of generative artificial intelligence, has reignited investor interest in the company. CEO Gary Smith stated during a December conference call that this growth opportunity is expected to significantly contribute to Ciena's anticipated growth rate for 2026, predicting a revenue increase of approximately 24%, the fastest since 2011. On the same day, Ciena's stock closed at its highest level since 2001, while networking giant Cisco also saw its stock reach new heights. With the escalating need for AI capacity, Ciena’s finance chief, Marc Graff, noted that the availability of essential components, such as memory and optical parts, has become increasingly limited, leading to higher prices. To mitigate supply chain challenges, Graff emphasized the company's efforts to collaborate closely with key suppliers.